This commit introduces several improvements to the backup system.
* Backups are made every 8 seconds for buffers that have been modified
since the last backup.
* The `permbackup` option allows users to specify that backups should
be kept permanently.
* `The backupdir` option allows users to store backups in a custom
directory.
Fixes#1641Fixes#1536
Ref #1539 (removes possibility of race condition for backups)
This change introduces header files for syntax files. The header
files only contain the filetype and detection info and can be
parsed much faster than parsing a full yaml file. To determine
which filetype a file is, only scanning the headers is necessary
and afterwards only one yaml file needs to be parsed. Use the
make_headers.go file to generate the header files. Micro expects
that all default syntax files will have header files and that
custom user syntax files may or may not have them. Resolving
includes within syntax has not yet been implemented. This
optimization improves startup time.
Ref #1427
With the new backup option, the autosave option is no longer useful.
Since it never really worked well in the first place, it has been
removed.
Closes#1420
