Add pkg-config gc flags to llvm Makefile

This makes building work for systems which have gc installed in a
non-standard location.  The invocation was pulled from
https://github.com/schani/clojurec/pull/2, and then modified based on
https://github.com/idris-lang/Idris-dev/pull/428#issuecomment-26302460.
data-lens is not a dep of idris

lens is, but that isn't available in the binary repos of the old version
of Ubuntu Travis-CI runs.
Set the handles used for --client to use UTF-8

Previously they were binary-mode, so they used char8 “encoding”, taking
codepoint values modulo 256, leading to cryptic identifier mangling errors
when using idris-vim.
javascript: optimize constructor allocation
javascript: inline some SLIDEs and PROJECTs
javascript: fix stray semicolon
suc{Max,Min}{L,R} + add mrb to CONTRIBUTORS
Fix typo in Idris network C code
Correctly count applications of variables in :search
Merge pull request #1347 from raichoo/javascript

Javascript
add system to Effects.System as is
add system to Effects/System neweffects
Add goal types to quasiquotes.

A quasiquote expression can be given a goal type for the elaborator,
which helps with disambiguation. For instance, `(() : ()) quotes the
unit constructor, while `(() : Type) quotes the unit type.  Both goal
types and quasiquote are typechecked in the global environment.
Merge pull request #1348 from david-christiansen/quasiquote

Add goal types to quasiquotes.
Merge pull request #1346 from bmsherman/searchVarMatching

Correctly count applications of variables in :search
Merge pull request #1344 from mrb/maximum_succ_proof

suc{Max,Min}{L,R} + add mrb to CONTRIBUTORS
javascript: simple dead code elimination
Merge pull request #1349 from raichoo/javascript

javascript: simple dead code elimination
Predicates for Prelude Strings
Merge pull request #1229 from LeifW/travis_deps

Don't bother installing data-lens