call InteractiveChecker.InvalidateAll after solution reloaded

add assertion to localize a bug with wrong symbol ranges
fixed: SourceCodeClassifier raises exception on indexers

recreate Checker for each solution
replace Atom holding LanguageService instance with a mutable field
cosmetics
Merge pull request #223 from vasily-kirichenko/invalidate-checker-on-solution-loading

call InteractiveChecker.InvalidateAll after solution reloaded
Initial version of integration tests
Merge branch 'release'
Merge pull request #228 from dungpa/integration-tests

Initial version of integration tests
add the integration tests project into the main solution

run the integration tests from the build script
delete integration tests solution
add FSharpVSPowerTools.Tests project into the solution

cleanup the main solution
Merge pull request #230 from vasily-kirichenko/run-integration-tests-from-build-script

Run integration tests from build script
Try to run tests as much as possible in CI
Merge pull request #233 from dungpa/build-script

Try to run tests as much as possible in CI
make DTE.GetActiveDocument safe
fixed: SyntaxConstructClassifier passes wrong file path to LanguageService
cleanup
do not raise exception in SyntaxConstructorClassifierProvider in case there is no active document

remove exception catching in DTE.GetActiveDocument
Merge pull request #232 from vasily-kirichenko/fix-colorizer-uses-wrong-doc

Fixed: SyntaxConstructClassifier passes wrong file path to Checker
fixed: VS crashes when solution closes
Implement stub generation for interfaces