#351 allow Bundle-RequiredExecutionEnvironment

3 commits :
- fix for #351 : allow `OSGI/EmbeddedDevice-1.0` as a valid value in the verifier for `Bundle-RequiredExecutionEnvironment`
- refactor the regex that does that check to use grouping with `[]` to improve efficiency and readability (for exemple `J2SE-1\.2|J2SE-1\.3|J2SE-1\.4|J2SE-1\.5` becomes `J2SE-1\.[2345]`)
- fix the regex to use strict matching by adding boundaries `^` and `$` (most patterns in that source probably also need the same fix)