add logs and fix a python path bug

The pserver checkpoint before failed because the MD5 checksum is
calculated incorrectly. Now changed to CRC32 checksum.

* fix gometalinter versioning

* stop gometalinter

* golang pserver optimizer config for user

* update

* update

* update

* update

* update by comments

* fix errors

* fix errors

* add start_record interface

* call master client in reader

* update

* add demo code in comments

* update comments

* delete unittest for recordio reader

* add master server unit test

* fix comments

* use t.Log

* fix travis can not fetch git repo

* fix git repo

* fix recordio split and task passes

* update for pre commit

* update

* update, still need to sync client wait for pass end.

* able to sync passes for task dispatching

* update to comment

* update

* fix yapf check

* why local pre-commit fails? version is the same

* fix race condition

* update

* fix race condition

* this still have duplicate problem in unit test

* update

* update

* update by comment

* update

* default learning rate, temperary fix

* update

It's already fixed by Wuyi's PR, but his PR may take some time to
merge, but I want to get this change in ASAP.

Unchecked errors could be handled by: cd go; gometalinter --vendor --disable-all --enable errcheck $(glide nv)

Fix fetch record from master

* using etcd as fault tolerant training

* update

* workable version, ft not tested

* small fix

* update

* remove TODO

The buffer allocation size should be number of bytes, not number of
floats.