Using just emaclient as editor if server-name is the default value.

Otherwise there are problem on windows (Closes #497)
There is still a problem with non standard server name on windows, but
this commit fix most common case.
fix travix make targets
Merge branch 'maint' of github.com:magit/magit into maint
fix travix make targets
only translate ansi sequences to properties when needed

Only translate ansi control sequences to text properties when colored
git output was explicitly requested.  Previously this was done for all
git output and as a result e.g. `magit-show's output was corrupted
when the shown file contained such sequences.  Fixes #544.