Initial commit
Removed dependancy on <eku\io\_io.h>

Added facility to test only anions and only cations instead of checking complete salt.
This had to be done because distribution of ions was not uniform.
For eg. there are many nitrates in ANAL_SALTS because they are always soluble while sulphides were uncommon as they are usually insoluble.

Added ability to convert 'ion(s)' to 'ion(aq)' in dissociating medium in function tube_t::react_prep()
I added more comments and cleaned up some code
Many changes
Imported code in chem.h from chem.cpp
Added some more functions. to chem.h
Made chem_gui.cpp, resource.rc and resource.h for GUI build.
Made chem_cmd.cpp for Command line build.
Some GUI changes