win-wasapi:  Use macros instead of strings

Instead of using strings for setting names, use macros.  Macros prevent
mis-spellings, prevent usage of the wrong name, and if you get it wrong,
it will simply fail to compile, helping to ensure that the right setting
value is being used.
Use uint8_t* instead of void* for texture data

NOTE: In texture_setimage, I had to move variables to the top of the
scope because microsoft's C compiler will give the legacy C90 error of:
'illegal use of this type as an expression'.

To sum it up, microsoft's C compiler is still utter garbage.
libobs:  Fill in rest of 'path' property code

A path should have a filter, default search directory, and a way to
indicate whether or not a directory or file is desired.
Implement 'path' property in to properties view
Add FFmpeg image file support to the core
Add MagickCore image file support to the core

MagickCore is provided here as an alternative to FFmpeg in case FFmpeg
is not easily supported (for example, debian-based linux distros).

NOTE: Cmake configuration needs to be changed in order to allow
MagickCore image support.
Add image source plugin

A simple plugin that does nothing more than display an image file as a
source.
Add image source module to obs-studio basic UI

...We really need to make this search for modules and automatically load
them.
Merge pull request #131 from jp9000/image-support

Implement image file support
Use older FFmpeg API functions for AVFrame

Compatibility with older FFmpeg versions may be broken if the av_frame_*
functions are used instead of the avcodec_* equivalents.
Add ImageMagic/Libavcodec find logic
Use propper ffmpeg compatiblity instead of relying on deprecated functions
Add missing header to CMakeLists.txt
Merge pull request #132 from BtbN/cmake_magick

cmake support for ImageMagic vs. libavcodec
Add '.directory' to .gitignore
Fix bug magickcore file loading freeze

This seemed to happen if the 'file' variable was NULL.  For some reason,
magickcore would just totally freeze.
Don't use swscale if format is supported
Set default blend function to srcalpa/invsrcalpha
Use signal/slot when creating a source via popup

I realized that there's no other way to share the menu if I want to add
it as a sub-menu somewhere else.
Give the 'add source' popup the 'Add' title

This allows the popup to be appended directly as an item for other
popups.