LMPC with Q3A support - start of implementation

Over the weekend I copied the demo relevant files from the Q3A source into the directory src/quake3 of LMPC. Then I activated by default the already existing DM3 support in the main compile infrastructure files and started implementing. First I converted the Q3A source from DOS line endings to UNIX line endings, changed all the C++ comments to standard C comments, and removed some GCC warnings. The next step was to create the library libquake3.a, which should contain all the needed parts of the Q3A source. I had to add several header files to make this happen.
The last step was to implement the function isDM3bin() in the file src/udm3.c. Thus the LMPC option --info works now on Q3A demo files too. All the rest will follow.
As usual I'll first implement the "binary read -> text write" part. To simplify this I'll use the already existing "node-tree as text" output code, which creates not XML but my own structured text (known from DEM, QWD, and DM2 text files). It's easy to write a XML backend later on.