Implement implicit conversions of function-call arguments (both in and out) as explicit conversions in the AST, through handleArgumentConversions().

Also
 - uniformly handle EvqConstReadOnly as an input argument in a function, with 
   isParamInput() and isParamOutput() queries in TQualifier.
 - provide a makeTemporary() in TQualifier, for erasing original qualification when making a temp
 - provide a makeInternalVariable() call to make a shader variable not seen in the shader source


git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@25912 e7fa87d3-cd2b-0410-9028-fcbf551c1848