cmake: remove FindQt5 module

Qt5 ships with a Qt5Config.cmake file itself, so a FindQt5.cmake file is
not necessary.
Fix compressed block width in PxFmt
Add support in Ktx textures for FXT1 compressed textures.

PxFmt library already supports this format but Ktx textures didn't.

Existing ktx texture code assumed compression blocks were square texels. Since
FXT1 compression is a non-square block (8x4), this required additional changes
to support non-square blocks.
Remove mipmapped_texture class and files.

Removed last usage of mipmapped_texture class.  Most straightforward way
was to just remove the last unused function (read_image_from_memory()) that was
using mipmapped_texture class.
Workaround to skip binding missing RenderBuffers rather than asserting

For a Dota2 trace there seems to be a snapshot bug that is not capturing all of the Renderbuffer state associated with FBs.  Upon restore I'm hitting an error due to various RB handles being invalid.  This change works around that error for the time being until root cause is fixed.
Initial addition of SSO API Tracing

This adds basic, buggy support for tracing SSO API calls.
Still needs further debug, but it at least allows a DOTA2 Source2 trace to be captured without reporting errors.
Remove some debug code.
Merge pull request #150 from tobin-lunarg/initial-sso-and-rb-restore-workaround

Initial SeparateShaderObject support and Renderbuffer restore workaround
Merge pull request #106 from jon-lunarg/pxfmt_07_28

Merge PxFmt changes and removal of mipmapped_texture class
Add Settings dialog that allows user to edit settings via json. There aren't many settings right now, but that is likely to change.
Merge pull request #101 from mathstuf/remove-findqt5

cmake: remove FindQt5 module
UI: Update CMakeLists to copy Qt5 dlls using variables from the official Qt5Config.cmake
Update README.md

Add information on building for Windows
Merge remote-tracking branch 'upstream/master'