First grammar for System Fomega.

Maybe it is actually better to use Agda.Syntax.Internal.Term,
and use dedicated constructors and views.
Abstract representation of Fomega syntax.
Fixed tags generation.
Renaming of identifiers to avoid confusion
[ gitignore ] Ignoring dyn files.
[ Fomega ] Explicit arrow and forall in type grammar.

WAS: subsumed under TCon, but this is impractical.
[ Fomega ] Constructors of Fomega expressions start with F now.
[ Fomega ] Implemented inductive instance of grammar.
[ Fomega ] First draft of type extraction.

Does not compile yet.
[ Fomega ] Added levels to Vec example extraction.
[ Fomega ] Added a second base kind KTerm.
[ Fomega ] Informal extraction examples: added lookup.
Merge remote-tracking branch 'master/master'
[ Fomega ] Fixed compilation of AgdaInternal.
Merge branch 'master' of github.com:agda/agda
Merge remote-tracking branch 'master/maint-2.4.2'
Some clarification of System Fomega syntax.
[ Utils ] Monadic pretty printing class.
[ Fomega ] Pretty printing of kinds.
[ Fomega ] Removed Pretty KindView' instance.