update export_all_courses management command to count and list all failed export courses

(cherry picked from commit 70e5044f479e0bfe6182c3cc2edc613cc77a7728)
OAuth signature should be verified against URL provided to the tool. There is possibility that a proxy will change URL along the way (for example protocol from https to http) which would invalidate signature.

(cherry picked from commit 8494473a0592908b948e17a9204b91f36bb20c28)
workaround for custom_tag being broken in residential MITx
Annotator Tools: Fix major logic bug in code

(cherry picked from commit 71e9f4488bf8b3c8b094da94cb69f0a8f141cdd7)
Merge pull request #4 from mitocw/bugfix/ichuang/custom_tag_workaround

workaround for custom_tag being broken in residential MITx
Corrected log type for LTI per @cpennington review
Merge pull request #5 from mitocw/mitx-hotfix-rc-20140828

Mitx hotfix rc 20140828