Layer refactor #2

[cbielow]

Description

• refactor getIntensity into layers
• some code cleanup and speed improvements

How can I get additional information on failed tests during CI:

If your PR is failing you can check out

• http://cdash.openms.de/index.php?project=OpenMS and look for your PR. If you click in the column that lists the failed tests you will get detailed error messages.

Note:

• Once you opened a PR try to minimize the number of pushes to it as every push will trigger CI (automated builds and test) and is rather heavy on our infrastructure (e.g., if several pushes per day are performed).