Added Custom Exception (InstrumentationException)

Signed-off-by: Kalyan <kalyan.menda@whiteskylabs.com>
Merge branch 'master' of git@github.com:kalyanwsl/wsl-usecases.git into mule-instrumentation-system
Added Usage.md file

Signed-off-by: Kalyan <kalyan.menda@whiteskylabs.com>
Merge pull request #28 from kalyanwsl/mule-instrumentation-system

Mule instrumentation system