Fix failing test when running mvn install

Some test cases in DerivedAllocationGeneratorTest were failing during
a mvn install. It might not happen in all systems since it depends
on the order the tests are executed. It's also failing if run
individually.

The problem is that ScenarioBootstrap must be executed before
executing these tests. When distributing the resources, the
DayAssignments of the resource for the current scenario are queried.
An IScenarioManager must have been registered in Registry plus the
main scenario initialized.

The stack trace is:

java.lang.IllegalStateException: loadRequiredData should have been called on org.libreplan.business.scenar
ios.bootstrap.ScenariosBootstrap
        at org.libreplan.business.scenarios.bootstrap.ScenariosBootstrap.getMain(ScenariosBootstrap.java:81)
        ...
        at com.sun.proxy.$Proxy42.getMain(Unknown Source)
        at org.libreplan.business.scenarios.OnlyMainScenarioAwareManager.getCurrent(OnlyMainScenarioAwareManager.java:38)
        at org.libreplan.business.resources.entities.Resource$UsingScenarioManager.calculateAssignments(Resource.java:185)
        at org.libreplan.business.resources.entities.Resource$DayAssignmentsState.getAssignments(Resource.java:172)
        at org.libreplan.business.resources.entities.Resource.getAssignments(Resource.java:886)
        at org.libreplan.business.resources.entities.Resource.getAssignmentsForDay(Resource.java:153)
        at org.libreplan.business.resources.entities.Resource.getAssignedDurationDiscounting(Resource.java:861)
        at org.libreplan.business.planner.entities.AssignedEffortForResource$AssignedEffortDiscounting.getAssignedDurationAt(AssignedEff
ortForResource.java:169)
        at org.libreplan.business.planner.entities.EffortDistributor$ResourceWithDerivedData.withAvailableCapacityOn(EffortDistributor.j
ava:232)
        at org.libreplan.business.planner.entities.EffortDistributor.resourcesFromMoreDesirableToLess(EffortDistributor.java:408)
        at org.libreplan.business.planner.entities.EffortDistributor.assignAllPossibleWithoutOvertime(EffortDistributor.java:387)
        at org.libreplan.business.planner.entities.EffortDistributor.distributeForDay_(EffortDistributor.java:356)
        at org.libreplan.business.planner.entities.EffortDistributor.distributeForDay(EffortDistributor.java:341)
        at org.libreplan.business.planner.entities.DerivedAllocationGenerator.createAssignments(DerivedAllocationGenerator.java:114)
        at org.libreplan.business.planner.entities.DerivedAllocationGenerator.generate(DerivedAllocationGenerator.java:68)
        at org.libreplan.business.test.planner.entities.DerivedAllocationGeneratorTest.forOneResourceTheHoursGeneratedAreGotFromAlpha(De
rivedAllocationGeneratorTest.java:205)
Avoid build warning

Specify the encoding used in the project instead of using the platform
default one. This could lead to not portable builds among different
platforms.
Remove no longer applicable comments
Use the same configuration as in other tests

Otherwise it creates a new Spring context instead of keeping using the
previous one.

This doesn't seem specially dangerous, but in some circumstances can
lead to idle transactions with associated locks that hang up the
execution of the tests. This happened with PostgreSQL version 9.1 in
WorkReportServiceTest.importValidDescriptionValuesToWorkReport().
Remove added exception types

This test was causing errors on CalendarExceptionTypeServiceTest
because it was leaving behind some CalendarExceptionTypes in the
database.