Creation of empty ProjectChecker

* Deactivated BuilderModel checking

(references #96)
Implemented ProjectChecker

* Gathered all checks (from Engine::pretestConsistency and BuilderPretestInfo) into ProjectChecker
* Improved check of generators consistency

(references #96)
Add check of monitoring

(references #96)
Reactivation of Model checking

* Moved check of function plugins presence from BuilderModel constructor to EngineProject constructor
* Cleaned code

(references #96)
Add check of units relations at BuilderDomain creation

(references #96)
Add a reverse orientation method for LineStringEntity

* Added About dialog window
Merge branch 'linestringgraph-reverse' of https://github.com/rabotin/openfluid into rabotin-linestringgraph-reverse
Observer packages and modification of market-bag structure

* Changed MarketPackage path attributes
* Created MarketSrcObserverPackage and MarketBinObserverPackage classes
* Added method which returns the installation path of each type package
* Changed environment paths for the new market-bag structure
* Adapted MarketClient class to the new classes and new paths
* Added tests
Functions packages

* Added function-path attribute in MarketPackage
* Added function-path attribute in RuntimeEnv
* Created MarketSrcFunctionPackage and MarketBinFunctionPackage classes
* Added tests
Modification of market-place structure

* Created enum for types packages in MetaPackageInfo
* Created maps of catalogs url, data and MetaPackages indexed by types
* Added typedef for maps
* Created a method to display in console packages sorted by types
* Adapted MarketClient and MarketClientAssistant classes
* Changed test market-place for new structure
* Added tests
Tests for types packages in market-place

* Added new test packages for MarketClient_TEST
* Changed name test-packages
* Added tests
Datasets packages

* Added dataset-path in MarketPackage class
* Added dataset-path in RuntimeEnv class
* Added member fluidx in SelectionType enumeration
* Created MarketDatasetPackage class
* Redefined process method for datasets
* Added tests
Merge branch 'devel-market' of https://github.com/chataignerm/openfluid into devel-market