Interactive functions for loading data and analysing results

New Shiny-based graphical interface functions:
- launchDiffExprLoader(): load differential expression data
- launchCMapDataLoader(): load CMap data
- launchResultPlotter(): view and plot data results
- launchMetadataViewer(): check metadata of a given object

Major changes

downloadENCODEknockdownMetadata(): metadata is now automatically saved to a file in order to avoid downloading metadata every time this function is run
plotTargetingDrugsVSsimilarPerturbations():
- automatically look for matching compounds in multiple columns of both datasets
- allow to manually select columns on which to merge datasets
prepareDrugSets(): drug sets based on numeric molecular descriptors are now prepared using evenly-distributed intervals
Simplified tutorial