fix Issue 11396 - Function alias declaration not valid according to spec
fix Issue 12802 - Allow optional 'StorageClasses' for new alias syntax
document implicit conversion rules
Merge pull request #583 from WalterBright/imp-conv

document implicit conversion rules
Merge pull request #582 from 9rnsr/fix_aliasdecl

Issue 11396 & 12802 - Allow optional 'StorageClasses' for old/new alias syntax