Gene type column and improved demo files

[1.10]

Added

• An additional Gene Biotype (build 37) or Gene type (build 38) column when downloading genes to file. This allows downloading of non-coding genes

Changed

• Demo files genes_37.tsv and genes_38.tsv to reflect latest changes in genes downloaded files
• Demo files contain now lines from the following genes: MTHFR, DHFR, FOLR1, SLC46A1, MT-TP (better integration with chanjo tests)