Classes for representing import data

* ImportData represents the whole project to be imported.
* ImportTask represent a single task.

FEA: ItEr77S05BasicProjectImport
Interface to import orders

Defines the generic interface to import external projects into the
Libreplan database.

FEA: ItEr77S05BasicProjectImport
First step to import orders using MPXJ

* Implement the interface OrderImporter using MPXJ
* Conversor from MPXJ file types to ImportData
* Modify pom.xml to add MPXJ dependency

FEA: ItEr77S05BasicProjectImport
Test for OrderImporterMPXJ and needed files

Added external needed project files. One .mpp and one .planner.

FEA: ItEr77S05BasicProjectImport
Import project web ui

Implements a page with a browse button to select a file to import.
Modifies CustomMenuControler to show the import option.

FEA: ItEr77S05BasicProjectImport
Renames ImportData to OrderDTO

FEA: ItEr77S05BasicProjectImport
Renames ImportTask to OrderElementDTO

FEA: ItEr77S05BasicProjectImport
Renames OrderImporter to IOrderImporter

FEA: ItEr77S05BasicProjectImport
Refactor package for stuff related to importers
Generate properly codes for order elements after importing a project

FEA: ItEr77S05BasicProjectImport
Adds Order and Dates fields

FEA: ItEr77S05BasicProjectImport
Writes the dates fields for Import entities

FEA: ItEr77S05BasicProjectImport
Creates new create methods for Task and TaskGroup

TaskSource has two new methods. One method for create a Task and other for create a TaskGroup
assinging them to the TaskSource.
Task has one new method to create a task without initialize its dates.

FEA: ItEr77S05BasicProjectImport
Import tasks and its dates

Creates and stores the TaskSources and Tasks needed to import the data.

FEA: ItEr77S05BasicProjectImport
Moves calculateAndSetTotalHours() to Order

FEA: ItEr77S05BasicProjectImport
Adds functionality to import task's total hours

FEA: ItEr77S05BasicProjectImport
Adds functionality to import the deadline

FEA: ItEr77S05BasicProjectImport
Adds functionality to imports milestones

FEA: ItEr77S05BasicProjectImport
Fixes the import of the deadline for planner files

FEA: ItEr77S05BasicProjectImport
Fixes the import of the tasks total hours

FEA: ItEr77S05BasicProjectImport