Issue #451: reworked travis and added PR desc testing

[rnveach]

Issue #451

[coveralls]

Coverage remained the same at 98.339% when pulling a11c7f8 on rnveach:issue_451_2 into c03e3d4 on sevntu-checkstyle:master.

[coveralls]

Coverage remained the same at 98.339% when pulling 9581524 on rnveach:issue_451_2 into c03e3d4 on sevntu-checkstyle:master.

[coveralls]

Coverage remained the same at 98.339% when pulling e9d7d10 on rnveach:issue_451_2 into c03e3d4 on sevntu-checkstyle:master.

[coveralls]

Coverage remained the same at 98.339% when pulling d31c1dc on rnveach:issue_451_2 into c03e3d4 on sevntu-checkstyle:master.

[coveralls]

Coverage remained the same at 98.339% when pulling dca1384 on rnveach:issue_451_2 into c03e3d4 on sevntu-checkstyle:master.

[rnveach]

@romani What do you think of this travis rewrite?
Before the build took 6 minutes. This build took 3 minutes.
The longest being eclipse-cs because of external downloads and sadly the other items need quick install of sevntu for further checking.

If it is all ok, I will squash and rename for #451 as this will include the PR testing.

[romani]

good !
please prepare for merge.

side note and probably as next step idea:
review https://github.com/checkstyle/sonar-checkstyle/blob/master/.travis.yml , split of travis stuff into two files will give user ability to launch easily build item on his side.

[rnveach]

@romani Squashed and renamed commit.

[coveralls]

Coverage remained the same at 98.339% when pulling 4362641 on rnveach:issue_451_2 into 1ca2b9f on sevntu-checkstyle:master.

[romani]

one day we need to question why we do "javadoc:javadoc" as separate step.
"mvn clean install" should be be enough.