Updated `README.md`

Fixed: Bad output file names when providing engine extension

Fixed: Fault tolerance for errors within both either the template fil…

…e or the context file when using `--watch` + Added: Prints errors only once in a `--watch` loop.

Updated `README.md` Help Usage section

Added an extra verbose level for trace level + Fixed: Removal of the …

…magic comment would remove extra strings.

Updated README.md