Fix for Haxe3.

For some reason this extra empty string was adding a single extra empty
string in the argument list for Popen, causing it to go crazy, which
subsequently caused everything to break. This fixes the issue.
Add trailing comma and remove trailing whitespace.
Remove a quick hack.
Fix how we check for server mode.

I can't tell exactly how the previous version worked, since it broke in
Haxe3 and switching back to Haxe2 to check is hard. But I've made it
simply pull the first line from the haxe default commandline output and
look for "(Haxe|haXe) Compiler X.X", which seems like it should work.
However I can't say that it does for certain because like I said I can't
switch back to check.
Merge branch 'master' of git://github.com/johnfn/haxe-sublime2-bundle into johnfn-master
more haxe2/3 compatibility