Also removed uint256 which is not needed (checksum256 type already exists).

boost::interprocess:vector has problems when POD are used; see boost ticket 13533. We've been struggling with this for a good while and it's even worse on boost 1.67. Since the fix in boost's ticket 13533 won't be available until boost 1.68, replace instances off boost::ipc::vector<char> with boost::ipc::basic_string

Made system_api a context api and created context_free_system_api for contrext-free actions.
Moved publication_time and current_time (now()) to context api.
Removed math_api that is no longer used.

Also:
* Disallow executing a proposed transaction if it has expired.
* Correct bug with return value of check_authorization (provided_delay
should not be considered in max_delay).
* Check expiration, TaPoS, and valid referenced accounts prior to other
transaction_context initializations (primarily to get more meaningful
error messages).

- update system contract with setram that properly updates market
pricing

Also replaced `provided_accounts` and `provided_levels` with just `provided_permissions` which can now replicate the behavior of `provided_accounts` by using the `empty permission_name` as a wildcard permission.

Also, check_authorization now accepts a `minimum_delay` which is currently not being used but can be used in a later change to the authority checking algorithm to optimize its search path.

better dispatching of inline actions and point checktime intrinsic directly to apply_context::checktime

Created builtins library for compiler-rt builtins we have to use, and reimplemented a few builtins as direct calls to this library

* clean up configuration parameters
* use dynamic max_inline_action_size configuration parameter to limit size of inline actions
* use dynamic max_inline_action_depth to limit recursion depth of inline actions
* change deferred_trx_expiration_window parameter into a dynamic configuration parameter
* add numerator and denominator configuration parameters for later context free data discount implementation
* bill delayed transaction for the additional net usage of the eventual retirement of the deferred transaction

Since the delay has now moved into the authority, the delay tests were not setting the delay properly in the updateauth actions.
This meant that a delay was not enforced and the tests were not actually testing delays properly.

I fixed the tests to properly set the delays, but this means that additional tests in delay_tests now fail.
The additional tests that failed are: link_delay_permission_change_test, link_delay_permission_change_with_delay_heirarchy_test, link_delay_link_change_test, and link_delay_link_change_heirarchy_test.
The reason these fail is very likely due to off-by-one errors due to change of now() from head block time to pending block time.

In this commit, I fixed link_delay_permission_change_test but have not yet gotten to the other three tests.

Also, of the two delay tests that were originally failing, I fixed canceldelay_test but have not yet fixed canceldelay_test2.

The now() intrinsic was replaced with a current_time() intrinsic which returns the current time (not head block time) in microseconds since epoch.

A now() function was defined in eosiolib/system.h which returns current_time()/1000000 so that existing contracts which use now() need minimal changes.

The publication_time() intrinsic was modified to also return the time as microseconds since epoch.
The only contracts that used publication_time() so far were for tests and those tests have been updated to reflect the new meaning of publication_time() and current_time().

Also, it now checks to ensure the proposed producer schedule would actually change the schedule.