Petitboot v1.7.0 tagged

[Samuel Mendoza-Jonas]

Petitboot v1.7.0 has been tagged. A number of changes were queued up in
master; a few notable ones are listed here or see the commit log for the
full details.

- Fine grained proxy control
	PXE conf files can now specify a HTTP(S) proxy inline which will
	be applied to the following boot options.

- Fix relative parsing for manual config files
	Boot options from a manually downloaded config file could be
	erroneously set relative to the root directory. A new parameter
	'pxeconffile-local' is added to avoid this.

- Add syslinux parser support
	Support for syslinux-formatted config files on block devices.

- Treat empty boot order as 'boot any'
	Change an empty boot order to behave as 'boot any' to be more intuitive
	to the user.