libobs: Add function for default module locale

This function is used to simplify the process when using the default
locale handling for modules.  It will automatically search in the plugin
data directory associated with the specific module specified, load the
default locale text (for example english if its default language is
english), and then it will load the set locale on top of the default
locale, which will cause text to use the default locale if the desired
locale text is not found.
libobs: Add macro for default module locale

These macros are used as easy helper functions to load/unload module
locale that's based upon the text_lookup system.  You simple place the
OBS_MODULE_USE_DEFAULT_LOCALE macro once in the module, call
OBS_MODULE_FREE_DEFAULT LOCALE in obs_module_unload, and then
call obs_module_text anywhere in your module where you need to look up
text.

By default, it will look for a locale directory in your module's data
directory, and look for language files within it (INI locale format)
Add locale for modules
Merge pull request #148 from jp9000/module-locale

Module locale