Adding invoke and landing pad to Wrapper.
Adding global functions.

setInitializer, getFirst and getNext for globals.
Adding setGlobalConstant.
Adding regular buildGEP.
Removing #if's for LLVM 2.x code.

This leaves the 3.0/3.1/3.2 specific code, but it may be a good idea to
just use the version control tags/branches to handle that?
Visibility, function parameter, and landing pad operations.
Adding count struct elements and get element type.
Add version check, remove list of versions.

The list of versions is gone 2.7, 2.8... etc.

Added a check for LLVMStructType which was introduced in 3.0 to check
for 3.0.
Adding changelog.
Merge pull request #64 from scottgw/master

Adding more of the global API and invoke/landingpad API to Wrapper.