The .travis.sh script was referencing "projects/gmake" and "projects/gmake.mac" as working directories, but the actual build system uses "projects/make" and "projects/make.mac". This fix updates both the default and macOS-specific paths to match the correct directory naming convention used by the project's make-based build system.
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.
