0023468: Include current branch name into default name of directory for test results

Default name for results directory is generated as "results_<branch>_<timestamp>".

In the HTML log of test execution references to script files are made HTML links to relevant files

Aded possibility to put data file for use by test script into subdirectory data of the script folder (function locate_data_file is extended to find such files).

Test demo/testsystem/A1 renamed to locate_data_file and corrected to account for the recent changes.

Default value of CSF_TestDataPath is defined pointing to $CASROOT/data

File psrse.rules corrected in accordance with changed message on missing data file

Interface of command testgrid changed:
- output directory (formerly required argument) is now defined by optional parameter -outdir
- by default tests are run in parallel mode with number of processes equal to number of system CPUs
- check for input arguments is made more strict
Treatment of parameter -outdir of command testgrid corrected.
Function locate_data_file and code to run tests in parallel revised to be usable with Tcl 8.4.
Adjusting testing case demo draw getsource for current state of master