Speedup travis build

[majst01]

Build should always be as fast as possible. so i did:

• create a travis matrix of JDK and Influxdb version
• run test against all influxdb versions only with the most current JDK, test with JDK8 only influxdb 1.5
• reduce the amount of points written in one particular Performancetest.

Total duration is now ~3min compared to 35min before.

[codecov-io]

Codecov Report

Merging #435 into master will increase coverage by 0.07%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             master   #435      +/-   ##
==========================================
+ Coverage     85.93%    86%   +0.07%     
  Complexity      292    292              
==========================================
  Files            20     20              
  Lines          1258   1258              
  Branches        131    132       +1     
==========================================
+ Hits           1081   1082       +1     
  Misses          116    116              
+ Partials         61     60       -1

Impacted Files	Coverage Δ	Complexity Δ
src/main/java/org/influxdb/dto/Query.java	65.78% <0%> (+2.63%)	12% <0%> (ø)	⬇️

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[majst01]

@fmachado what do you think ?