Implement new hashtag parsing for multiple citations.

Also separates hashtag parsing from DB interaction.
Updates relevant tests (without changing their content or intent).
added post updating test
Merge branch 'ketch/separate_parsing' for pull request #102
added tests for href and no #spnetwork handling
get rid of unneeded isRec test
broke out some tests to test_incoming
added test_text_content(), test_html_content(), test_paper_update()
renamed destructive test as destroy_db_and_test()
Update citation parsing to standard discussed with @cjlee112.
Merge branch 'separate_parsing' of github.com:ketch/spnet into separate_parsing

* 'separate_parsing' of github.com:ketch/spnet:
  Update citation parsing to standard discussed with @cjlee112.

Conflicts:
	spnet/test.py
Merge remote-tracking branch 'remotes/ketch/separate_parsing' into separate_parsing
fixed minor merge errors in PR #102 test.py
made tests clean up after themselves even with errors
moved Post.citations cleanup to Post.delete() method
added test for automatic citation deletion
added test for removal of post updated to remove spnetwork tag per issue #81
fixed issue #81
added test for citation updating for PR #102
added updating of paper bindings when a post is updated for PR #102
got rid of code using obsolete core.Recommendation class