update _git_version_git() to better parse `git branch`

Sometimes, `git branch` may output in color, which causes the regex search to fail.  Specifying --color=never fixes this.
Merge pull request #16 from mikegoodspeed/patch-1

update _git_version_git() to better parse `git branch`
Use cdecimal to speedup
Fix overflow in GetDataDecimal
Fix overflow in GetDataDecimal
Merge pull request #26 from jbq/master

Use cdecimal to speedup
Merge pull request #27 from jbq/bugfix2

Fix overflow in GetDataDecimal
prepare ground for next serial
Merge branch 'master' into v3-virtuoso

Conflicts:
	setup.py