Says 'Download' when only one seq. is present

The change is made directly into the fasta.erb, as use of Javascript
seemed unnecessary.

Signed-off-by: Vivek Rai <vivekraiiitkgp@gmail.com>
Disabled cursor on labels too, Refactor css

Due to specific CSS on classes, the behavior of cursor pointers was
little ambiguous. Despite selecting a nucleotide db, one can see
selectable pointer on protein db label. This is fixed now.

Also, remove other unnecessary CSS customizations.

Signed-off-by: Vivek Rai <vivekraiiitkgp@gmail.com>
Grey out uneligible checkboxes, labels

Signed-off-by: Vivek Rai <vivekraiiitkgp@gmail.com>