Tests: Apply proper settings for compilation tests
Compilers: Fix MEF import issues

Properly export & import MEF-powered classes
Compilers: Fix execution order issues

Don't call virtual methods in constructors.
Or at least make sure the overrides actually work.
Minification: Ignore derived content types

Don't try to minify LESS files
Bundles: Ignore bad extensions
Settings: Remove unused property

Also fix migration mapping
Settings: Fix legacy settings locator

Also fix new global settings path
to use per-user directory.

Also update ConfOxide to save formatted JSON,
Settings: Skip invalid legacy enum values
Margin: Fix pane width serialization

Don't choke on bad values
Don't save NaN
Use original value name
Tests: Test basic LESS compilation
Tests: Expand compilation tests

Test minification & disallowed extensions

Fixes two bugs.
Tests: Fix compilation tests

Don't test against same compiled output
(LESS tests were totally broken)

Fix broken LESS expectation files
Read expected output before compiling