Get rid of jenkins client

[mvysny]

1. The dependency list is HUGE
2. Can't fetch a subset of BuildWithDetails for last 10 builds; the entire BuildWithDetails is huge since it contains the entire build log.
3. Replace with JSON queries

The dependency list:

+--- com.offbytwo.jenkins:jenkins-client:0.3.8
|    +--- com.fasterxml.jackson.core:jackson-annotations:2.3.4
|    +--- com.fasterxml.jackson.core:jackson-core:2.3.4
|    +--- com.fasterxml.jackson.core:jackson-databind:2.3.4
|    |    +--- com.fasterxml.jackson.core:jackson-annotations:2.3.0 -> 2.3.4
|    |    \--- com.fasterxml.jackson.core:jackson-core:2.3.4
|    +--- dom4j:dom4j:1.6.1
|    |    \--- xml-apis:xml-apis:1.0.b2 -> 1.4.01
|    +--- net.sf.json-lib:json-lib:2.4
|    |    +--- commons-beanutils:commons-beanutils:1.8.0
|    |    |    \--- commons-logging:commons-logging:1.1.1 -> 1.1.3
|    |    +--- commons-collections:commons-collections:3.2.1
|    |    +--- commons-lang:commons-lang:2.5 -> 2.6
|    |    +--- commons-logging:commons-logging:1.1.1 -> 1.1.3
|    |    \--- net.sf.ezmorph:ezmorph:1.0.6
|    |         \--- commons-lang:commons-lang:2.3 -> 2.6
|    +--- com.google.guava:guava:17.0
|    +--- commons-lang:commons-lang:2.6
|    +--- commons-io:commons-io:2.4
|    +--- org.apache.httpcomponents:httpclient:4.3.6
|    |    +--- org.apache.httpcomponents:httpcore:4.3.3
|    |    +--- commons-logging:commons-logging:1.1.3
|    |    \--- commons-codec:commons-codec:1.6
|    +--- org.apache.httpcomponents:httpcore:4.3.3
|    +--- org.apache.httpcomponents:httpmime:4.3.6
|    |    \--- org.apache.httpcomponents:httpclient:4.3.6 (*)
|    +--- jaxen:jaxen:1.1.6
|    +--- org.slf4j:slf4j-api:1.7.21 -> 2.0.6
|    \--- xml-apis:xml-apis:1.4.01