Draw shaded box
Add `delete` API and `del` command

This is just done on memory, and does not write back to a floppy disk.
Read RTC and Add `now` command to print current time
Move FILEHANDLE definition from mtask.h to file.h
Change `fopen` not to copy file data
Change `tview` to handle cursor key
Change `file_loadfile` to use `file_read`
Create function to handle key event for console
Use `draw_shaded_box` to draw buttons
Move console related functions into console.c
Split source file for `hrb_api` function
Widen console window
Remove `sincurve` application
Rename sht to sheet
Add `convert_image8` function to convert ascii string to bitmap image
Hide function
Change `make_window8` to receive SHEET
Add -s option to delete symbols
Standardize headers
Move `sprintf` definition from apilib.h to stdio.h