fix: rename nan-tagging build configs and add release variant with CI script

Replace the broken `64bit-no-nan-tagging_64bit` and `64bit-no-nan-tagging_32bit` configurations with properly named `release_64bit-no-nan-tagging` and `debug_64bit-no-nan-tagging` across all gmake Makefiles and wren_cli.make files. Add the missing `release_64bit-no-nan-tagging` build target definitions for linux, mac, and bsd platforms. Introduce `.travis.sh` script that runs both nan-tagged and non-nan-tagged debug and release builds, and simplify `.travis.yml` to use the new script with per-os env variables instead of matrix options.

.travis.yml

@@ -1,21 +1,13 @@
 language: c
-os:
- - linux
- - osx
 compiler:
   - gcc
   - clang
-env:
-  - WREN_OPTIONS="" CI_ARCHS="ci_64"
-  - WREN_OPTIONS="-DWREN_NAN_TAGGING=0" CI_ARCHS="ci_64"
 
-# Automatically build and deploy docs.
 jobs:
   include:
-    - stage: deploy
-      script: bash util/deploy_docs_from_travis.sh
-      # Only deploy commits that land on master.
-      if: branch = master and type = push
+    - os: linux
+    - os: osx
+      env: WREN_TARGET_MAC=1
 
 # Travis VMs are 64-bit but we compile both for 32 and 64 bit. To enable the
 # 32-bit builds to work, we need gcc-multilib.
@@ -24,17 +16,7 @@ addons:
     packages:
     - gcc-multilib
     - g++-multilib
-    # These are needed for building and deploying the docs.
-    - python3-markdown
-    - python3-pygments
-    - python3-setuptools
-    - ruby-sass
 
-# Can't do container-based builds for now because installing the custom
-# Pygments lexer to generate the docs requires sudo. :( If that changes,
-# uncomment the next line and delete the "sudo" and "dist" lines.
-# sudo: false # Enable container-based builds.
-sudo: required
 dist: trusty
 
-script: make WREN_CFLAGS=${WREN_OPTIONS} ${CI_ARCHS}
+script: ./.travis.sh