change detect script to just use sh

[finishes #46635507]
silence nokogiri install and don't install docs
add empty fixtures
Use cached JRE
Return fetched file path
WIP, replaced nokogiri with REXML, tests green
Refactor web_xml_config
Remove nokogiri includes
Revert "Remove nokogiri includes"

This reverts commit 9554f42c3b708d17fb05974462e36eb0cd7a1376.
Replace nokogiri with REXML
Remove nokogiri references [#46842625]
VCAP_APP_PORT -> PORT

fixes #6
Remove pry: not necessary for buildpacks
Include Code Climate badge
Fixed a blank init-param for the servlet [fixes #47881367]
Always call the subject during the detect specs
Upgrade Tomcat

Previously the Cloud Foundry Java Buildpack used Tomcat 7.0.37 when
hosting web applications.  This version of Tomcat has known
vulnerabilities and therefore needed to be upgraded.  This change
upgrade Tomcat to 7.0.40.

[#49892467]
Merge 49892467-tomcat-upgrade to master

[Completes #49892467]
Travis and dependencies updates

This change adds configuration to the Travis build to ensure that it
is tested on both 1.9.3 and 2.0.0.  In addition, it instructs travis
to notify our projectmonitor instance when builds complete.  This
change also updates dependencies to their latest versions.
Default JRE version change

Previously, the default version of Java was 1.7 unless otherwise
specified.  As Java 1.6 is EOL, this wasn't the best situation.  This
change updates the default to 1.7.

[#49892507]