partialWaveFit: Fix wave name escaping.

[legordian]

Fix the treatment of the TString with the wave name which is fed to the TPRegexp so that the new wave name convention works as well.

[suhlatwork]

I would prefer not merging this:

• escaping the special characters used for regular expressions at one point starts to hinder the usage of regular expressions, for that reason I would prefer not to do any escaping here (and even remove the current one), users of this functions can always pass an already escaped wave/amplitude name
• a function to escape the characters special for regular expressions already exists (escapeRegExpSpecialChar) but needs slight improvements ('^' is handled twice, double escapes '\' are not collapsed to one '\') but should be used instead of listing all characters here again

[legordian]

You are right, closed without merging. See also Issue #102 and Issue #101.