Hotfix - reusing ACS token.
Minor cleanup changes.
Merge pull request #48 from ivan-shaporov/dev

Hotfix - reusing ACS token.
Avoid multiple concurrent requests of ACS tokens.
Explicit lock object for ACS token refresh.
Make the lock object static.
Merge pull request #49 from ivan-shaporov/dev

Avoid multiple concurrent requests of ACS tokens.
Merge pull request #50 from WindowsAzure/dev

Merge code from dev branch for avoiding multiple concurrent requests of ACS tokens.