ConvSym: Support additional information for symbols

[vladikcomper]

A goal for the next major release of ConvSym would be to support the following additional information for symbol generation:

• Optional code/data flag - determines whether a symbol points to code or data;
• Optional source file and line information - lists which source file and line a symbol resides on.

[vladikcomper]

Since MD Debugger's Error Handler is now included in SGDK, source-line information will definitely come in handy there.

Note that this will be implemented in the next major version of my Debug Information (DEB) format, because the current version (DEB2) doesn't have a capacity for that.