Fix config parser

[InsanePrawn]

Hi,
in its current state, the config parser would reject empty lines and comments that do not include a '=' character as syntax errors, since the check for '=' happens before the check for the comment indicator.
I fixed that.
Also, I saw a small bug possibility in that the parser never trimmed the whitespace of the value section of the key=value pair, so key= value would've resulted in value being " value". I could not imagine a scenario in which this might be wanted or useful, so i added a trim() for that.
I'm using the master branch on my desktop machines since there still is no 4.13 compatible release.

[coveralls]

Coverage increased (+0.003%) to 46.741% when pulling 5da1e69 on InsanePrawn:master into ddb2511 on dkopecek:master.

[dkopecek]

LGTM. Thanks a lot!