add codepy caching test

Closes #113

See merge request inducer/loopy!196

C exec cleanup

See merge request inducer/loopy!195

Fix C&P bug in handling instructions with conflicts_with_groups

See merge request inducer/loopy!194

Had instructions conflict with all the groups they belong to - yucc.

Dep resolution: Speed up resolution in the common case where the

Closes #111

See merge request inducer/loopy!193

dependency is not a wildcard.

Related: #110

Also fixes treatment for self-dependencies in wildcards (closes #111).

Add concept of atomic load, implement atomic_inits

See merge request inducer/loopy!134

Fix for bad host code generation for CTarget and more cleanup

See merge request inducer/loopy!192

# Conflicts:
#   loopy/target/c/__init__.py

move host code generation to ExecutuableCTarget, add test to ensure we generate valid code with global temporaries present for C

include ExecutableCTarget in main __init__ and docs

See merge request inducer/loopy!191