Make helpex to be able to work with more xhp files at one time
- Add new input flag "-mi" which means multiinput
- Input is a file include pathes to xhp files
(these are in the same directory so their strings
are in the same po file)
- Output is a file include pathes to dest xhp files
- Merge reads all po entry from the specified po file
if MergeDataFile ctor's second parameter is empty
Rewrite makefiles to work with new syntax
Plus Delete some unused code
Change-Id: I5eb12d7a6f5e9cda378788410d3c50052eb752b8
Fallback to en-US is done in translations module. Fallback to
other languages is not supported, but if we ever needed it, it
would be easier to solve the problem in a script language
instead of C++ in translations module.
