Cleanup Greater than and Less than asserts from other PR (#264) (Thanks @dpostorivo and @Dommar92 !)

Rewrite UnityPrintFloat to match printf("%.6g").

The existing implementation was not very good:
 - It printed all very small values as "0.000000..."
 - It did not distinguish positive and negative zero
 - In some cases it printed extra garbage digits for single-precision values
   (e.g. 3.9e+30 was printed as 3.90000013+30)

Tests have been updated to check that we now match printf("%.6g") for
1,000,000 randomly chosen values, except for rounding of the 6th digit.

Allow specifying custom header declaration (Thanks!)

The user can specify UNITY_OUTPUT_CHAR_HEADER_DECLARATION and
UNITY_OUTPUT_FLUSH_HEADER_DECLARATION when he would like to declare
UNITY_OUTPUT_CHAT or UNITY_OUTPUT_FLUSH respectivly

- Fixed some style issues.

Fixed UNITY_TEST_ASSERT_EACH_EQUAL_*

Fixed copy-paste error for:
- UNITY_TEST_ASSERT_EACH_EQUAL_INT64
- UNITY_TEST_ASSERT_EACH_EQUAL_UINT64
- UNITY_TEST_ASSERT_EACH_EQUAL_HEX64

So that the comparison is done on the expected _value_ instead of the _array_.

Convert PDF docs to markdown (Thanks for all the work, @wolf99 !)

Add newlines after headings for best practice, trim trailing spaces & convert sneaky incorrectly coded chars

blank newline after headins is apparently best practice according to http://stackoverflow.com/q/42953462/1292918

Add GFM version of getting started guide PDF

Add GFM version of configuration guide PDF

Add GFM version of helper scripts guide PDF

Add GFM version of coding standard PDF

Add GFM version of assertions reference PDF

Change markdown used to italicise line. Switched to use asterisk markdown instead

Started to flesh out rubocop settings for this project. Added rakefile tasks to do so. Updated first script to make it compliant.

Starting to enforce our coding style. The first step is that we’ve pulled in Rubocop to check out Ruby syntax. There is likely a bit of customization to do yet AND there is definitely that backlog of todo’s that we just told it to ignore.