Add g:templates_global_name_prefix option
Change default global template prefix to work with macs

The colon character causes issues on OSX. '=template=' isn't the
prettiest, but it works, plus the user can change it to something nicer
if they want. Fixes #29
Some doc fix
Merge pull request #31 from Dewdrops/doc-fix

Some doc fix
Fixes #30

Ensure that filenames for templates are safe to be opened and wont shell expand to multiple file names
Use vim function for escaping filenames
Also fix TLoadCmd

This was also affected by #30. To fix, the common code between
TLoad and TLoadCmd was unified.
Merge pull request #2 from muff1nman/prevent-shell-expansion

Prevent shell expansion