More flexible tape/disk targets/layout

[cpcitor]

Currently, project is assumed to have a main target which is a binary file derived from C source code. Ancillary make targets make it possible to include other files in tape or disk image, including text files named like *.bas.txt and automatically converted.

Adjust to allow any target in any order (order is especially important for tape). Possibly default rules would insert BAS first then BIN etc.