Restored builtin inlining
Fixed inlining subbing non immutable bindings names in new scopes.
Cleaning up code a bit
Improved constant folding involing parameters
Cleaning up ecma_peep a bit.
Cleaned up compiler fn
Loosened identiifer replacement rules.
Remove old code
Added basic reachable binding pruning
Initial work on removing unreachable bindings.
V0.3.13
Fixed package with imports
V0.3.14
Fixed globals being marked unreachable.
Fixed if statements not being considered during reachability check.
V0.3.16
Prune globals if inlining makes them unreachable mattbierner/khepri#100
Fixed for statements inits being marked unreachable
V0.3.17
Fixed package generation for imports