Add CDTQProjectedDocumentRevision subclass

This subclass of CDTDocumentRevision overrides -mutableCopy to return
the non-projected version of the document's body to avoid data loss
by accidentally overwriting a document with its projection.
Log error messages for common Query issues
Correct class doc on format of database used in indexes
Update CDTDatastore to 0.10.0
Import logging headers
Add indexing performance numbers
Update CocoaLumberjack to 2.0.0-beta3
Deleting indexes now works
Gracefully fail when using duplicate field names in index
Add :git clone URL to pod line in README
Merge pull request #21 from cloudant/20-revision-subclass

Add CDTQProjectedDocumentRevision subclass
Add some performance tests (ignored by default)
Add invalid syntax tests for $or operator

Add array comparison tests and create indexes for documents
Abort query when compound operator does not have an argument of NSArray
Abort query when compound operator Array does not only contain dictionaries
Bail from query when argument dictionary to operator is empty
Add $lt and $gt tests
Add an array compare test
Add $eq tests

Add $eq tests and logic to abort query when test syntax is invalid
Update tests for $eq operator to use correctish syntax where  appropriate
Fix $lt $gt tests

Closes issue #24

Fix issue where index was not defined, for $lt and $gt tests.
Also corrected expected outcomes from the tests
Attempts to fix Query

Query attempting to fix @{@"name":@{@"$eq":@[@"mike"]}}
Fix query mentioned in last commit