Refactor DynTypedMatcher into a value type class, just like Matcher<T>.

Summary:
Refactor DynTypedMatcher into a value type class, just like Matcher<T>.
This simplifies its usage and removes the virtual hierarchy from Matcher<T>.
It also enables planned changes to replace MatcherInteface<T>.
Too many instantiaions of this class hierarchy has been causing Registry.cpp.o to bloat in size and number of symbols.

Reviewers: klimek

CC: cfe-commits, revane

Differential Revision: http://llvm-reviews.chandlerc.com/D1661
<rdar://problem/14496092>

Fixed an issue with reexported symbols on MacOSX by adding support for symbols re-exporting symbols. There is now a new symbol type eSymbolTypeReExported which contains a new name for the re-exported symbol and the new shared library. These symbols are only used when a symbol is re-exported as a symbol under a different name.

Modified the expression parser to be able to deal with finding the re-exported symbols and track down the actual symbol it refers to.
Fix creating bitcasts between address spaces in SCEV.

The test before wasn't successfully testing this
since it was missing the datalayout piece to change
the size of the second address space.