Improving loading and drawing of TMAP from textual spec

src/main/java/tmltranslator/TMLMapping.java

src/main/java/tmltranslator/TMLMappingTextSpecification.java

src/main/java/tmltranslator/TMLModeling.java

src/main/java/ui/DrawerTMAPModeling.java

src/main/java/ui/MainGUI.java