API changes (indexOfFirstChild etc)

Created GLAArrayInspecting protocol for read-only operations.
Added typedefs for block arguments.

API changes: (indexOfFirstChild etc)
Added:
<GLAArrayInspecting>
- (id)childAtIndex:(NSUInteger)index;
- (NSUInteger)indexOfFirstChildWhoseKey:(NSString *)key
hasValue:(id)value;
- (NSIndexSet
*)indexesOfChildrenWhoseResultFromVisitor:(GLAArrayChildVisitorBlock)chi
ldVisitor hasValueContainedInSet:(NSSet *)valuesSet;
- (NSArray *)filterArray:(NSArray *)objects
whoseResultFromVisitorIsNotAlreadyPresent:(GLAArrayChildVisitorBlock)chi
ldVisitor;
<GLAArrayEditing>
- (BOOL)removeFirstChildWhoseKey:(NSString *)key hasValue:(id)value;

Removed:
- (NSIndexSet *)indexesOfChildrenWhoseKeyPath:(NSString *)keyPath
hasValue:(id)value;
- (NSIndexSet *)indexesOfChildrenWhoseKeyPath:(NSString *)keyPath
hasValueContainedInSet:(NSSet *)valuesSet;
- (NSArray *)filterArray:(NSArray *)objects
whoseValuesIsNotPresentForKeyPath:(NSString *)keyPath;