Adds some constructors and moves the code to the header file. Uses some of the new constructors.
A big problem with the source are the different strategies used for otherwise similar classes.
E.g. a IrField registers itself with the VarDeclaration. Same is required for IrParameter, but
in this case it is done by the caller.
Previously, we just had a hack to make ref foreach statements work.
This commit enables them to work in other cases as well, like the
implicit __result variable for functions with out-contracts (which
is such a magic ref variable for ref-returning functions).
Fixes DMD testcase 'testcontracts'.
Fixed function literals in static initializers.
Changed alignment of delegates from 2*PTRSIZE to just PTRSIZE.
Changed errors to go to stderr instead of stdout.
Fairly major rewriting of struct/union/class handling, STILL A BIT BUGGY !!!
