- modularized plot download

Added:
- download CSV with cellIDs and cluster assignment
- download CSV after cleaning

Initial commit

UI overhaul: side panel added

Added: colour trajectories according to their filteirng status, if mid.in column available in the dataset.

Added:
Load button
F-n data4trajPlot that prepares data based on column selections in the UI

Error shows up in app log when plotting.

"Warning: Error in <Anonymous>: cannot open file 'Rplots.pdf'"

Fix based on: https://github.com/ropensci/plotly/issues/494

Added in plotting f-n:
if (names(dev.cur()) != "null device") dev.off()
pdf(NULL)

shinyjs library added to ui.R