Prepender64 -- add advanced linker-like features

[pararaum]

When loading the files support the advanced features akin to the "cbmtools" cld tool:

Loading: (file -> memory buffer)
  <file>[,,[<offs>][,<len>]]        - normal
  <file>,<addr>[,[<offs>][,<len>]]  - override load address
  <file>@<addr>[,[<offs>][,<len>]]  - raw file

[pararaum]

• https://stackoverflow.com/questions/14265581/parse-split-a-string-in-c-using-string-delimiter-standard-c
• https://stackoverflow.com/questions/5734304/c-boost-split-string
• https://en.cppreference.com/w/cpp/string/basic_string/getline