bugfix

bug fix. continue keyword is not valid
inside of `if` statements. we can achieve intended functionality
by using the `:` builtin. this is unclean and needs to be fixed,
but works in the meantime.

Replication steps:
1. Set `continue="true"` in config file.
2. `scdl <url>` - OK
3. `scdl <url>` - downloading the same url returns with `/scdl: line 69: break: only meaningful in a 'for', 'while', or 'until' loop`

The bug can be traced to `echo "MSG" && $cont`, which breaks when "$cont" expands into `continue` inside of an `if` statement.