* Portable plugin executable check for Windows platform
builds Windows and non-Windows platform plugin verifier separately
* Removes redundant build tag and file suffix, uses file suffix
As we'll need either to mention, which file compiles for which
platform.
* refactor(plugins): Improved and simplified verifier and plugin list
* Added proper executable check for current user
* Refactor plugin_list to make it more straightforward
* Seperate errors and warnings
* Don't return an error when no plugin is installed and `plugin list` is called
* Simplified tests
* Check assumption that a prefix is given in verify()
* fix(plugins): Fixed broken homedir expansion
* fix(plugin): Adapted to proper permission handling
E.g. if u-x, g+x and the user has the group of the file, but is also owner of the file then he is not allowed to execute the file.
* test(plugins): Added checks for the execution check for plugins
* chore(plugins): optimized tests to reflect the real unix behaviour
* chore(plugins): Moved plugin seenMap to top-level verify method.
Also, allow symlinks without warnings.
* refactor(plugins): Split up some methods in plugin_verifier to make them shorter
* fix: Tuned `plugin list` for better handling when no plugin directory exists