Set the property value classes on RKPropertyMappings when they are assigned to an RKObjectMapping.  This speeds up the mapping process significantly.
Add API to RKObjectMappingMatcher to be able to supply a dictionary of values to object mappings, so a value in a source map can do a single lookup to find the corresponding RKObjectMapping, instead of doing an iterative search through a number of individual RKObjectMappingMatchers.  To support the -objectMappings method of RKDynamicMapping, this required adding a new method to RKObjectMappingMatcher which can supply an array of possible RKObjectMappings to be returned.  Additionally, made that method return a constant array instead of creating a new one every call, as it gets called during the mapping process, which should further help performance when using dynamic mappings.  Also added an API so that a list of RKObjectMappings can be passed in with an evaluation block, again to better support the -objectMappings method.
Update code to add a block matcher rather than change RKDynamicMapping directly, which should be more flexible anyways.
Addressed a couple of pull review comments -- updated some docs, and changed a local variable name
Merge pull request #2095 from carllindberg/2065-PrecomputePropClass

Compute RKPropertyMapping.propertyValueClass early
Change init methods to use instancetype per PR request
Merge pull request #2093 from carllindberg/2065-DynamicMappingEnhancements

RKDynamicMapping enhancements
Minor adjustments to prevent core data concurrency assertions.

Assertions arise with '-com.apple.CoreData.ConcurrencyDebug 1' debug argument enabled.
Merge pull request #2096 from ppierson/core_data_concurrency_fixes

Core data concurrency fixes
[Bundle] Update
[Vendor] Update RKValueTransformers to v1.1.1
[Podspec] Update iOS deployment target to 5.1.1
[Rakefile] Use run instead of system
Update RKTwitter example project file
Bump version to v0.24.0
Merge branch 'release/0.24.0' into development