Update README.md with different possibilities to check out the source:
* stable versions should be tagged, a tarball is automatically generated and can (and should) be downloaded.
* development version ist just the git clone.
Add ar-lib file to gitignore, produced by autogen.
Precompiler voodoo for CINT to work around issue with FTD2XX library.
Solution from here: (japanese...) http://d.hatena.ne.jp/oxon/20100516/1273974318
Merge pull request #4 from simonspa/devel-DTB

start of refactorisation