Function attribute migration.

Function attribute migration.
Now all function attributes (args, critical, interrupt etc) are in the
sym_link where DECLARATOR==FUNCTION instead of scattered around in
the symbol and the etype of the symbol.
Now we can have multiple functions in a typechain which can have their own
private attributes.

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@1430 4a8a32a2-be11-0410-ad9d-d568d2c75423