Allow system cpptoml
meson.build: When the 'wrap_mode' option is set to 'nodownload' use a system version of cpptoml. This does not require using git and having a network connection during build, which is important for Linux packaging infrastructure.
subprojects/cpptoml.wrap: Pin revision to last release tag (v0.1.1).
lib/wptoml/*.cpp: Remove 'include/' prefix from all cpptoml related includes, at is not required.
Closes #17 (closed)