Fix modal dialog display

Visual Studio unfortunately must be aware of any model dialogs while
they are visible.  This changes the Rename dialog to call into the
EnableModeless API as appropriate during display
add ProjectCache.ProjectChanged
call InteractiveChecker.InvalidateConfiguration instead of InvalidateAll
fix a comment
change default colors for Depth Colorizer

rename a couple to functions
rename a module
Merge pull request #83 from vasily-kirichenko/master

Use InteractiveChecker.InvalidateConfiguration instead of InvalidateAll if a project changed
Merge pull request #85 from jaredpar/fixes-modal

Fix modal dialog display
Merge pull request #67 from OkayX6/master

Port CodeFormatting from C# to F#
Minor cleanups
Reinforce code style take 1

- Use 'x' for instance names consistently
- Use 'as self' to refer to instance names in constructor declarations
Reinforce code style take 2

- Module functions are camelCase
- Type members are PascalCase
Reinforce code style take 3

- Remove unused parameters (which have '_' prefix)
- Type annotation should use ': ', not ':' or ' : '

Address #86
Add a contribution guideline