Support for importing multiple XSLT formats

Have information of multiple XSLT files on an array for importing
"alien" formatted XML dive log files. Adding support for new XSLT
requires updating the array and adding the XSLT file (provided the
format can be identified by root element of the XML).

Signed-off-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>