Revert "ENGINE-1116: Removed dead code from BOS"

This reverts commit 6b9be0e5b8469c1fa39b0ba550cb9fc082cb209a.
Revert "ENGINE-1116: Removed dead code from BOS"

This reverts commit 905496aafd66018f5407c8d18e73abd848677d02.
Revert :
- ENGINE-1159 : Add unit tests on activity instance service
- ENGINE-1159 : Execute Task on behalf
- ENGINE-1158 : Add a new field (startByDelegate) in process instance, to start a process instance on behalf
updated javadoc according to Christine's review


Conflicts:
	bpm/bonita-api/bonita-common-api/src/main/java/org/bonitasoft/engine/bpm/supervisor/ProcessSupervisor.java
ENGINE-1000: Fix the size of the clob column
ENGINE-733 : Fix random errors on MySQL
ENGINE-1045: Support SQLServer
ENGINE-1045: Support SQLServer
[ENGINE RELEASE] Created the release 6.0.1-rc-02
[ENGINE RELEASE] Created the next snapshot 6.0.1-rc-03-SNAPSHOT
ENGINE-1498 : Dependency conflict when using same external libraries in two pools connected by call activity
fix typo
ENGINE-1000: Improve search on profile members
[ENGINE-1526] : stop using the MultiParentClassLoader in order for Tomcat to walk into the classloader hierarchy, so it will find 
out that we are executing some code in a classloader whose one parent is handled by himself. Then it will show the JNDI 
tree relative to the web application.
[ENGINE RELEASE] Created the release 6.0.1
[ENGINE RELEASE] Created the next snapshot 6.0.2-rc-01-SNAPSHOT
ENGINE-1526 : Add tests to prove bug
ENGINE-1550, fix failing test on bos
ENGINE-1550, fix failing test on bos
[ENGINE RELEASE] Created the release 6.0.1