.travis.yml: rework according to new travis-ci infra

- install using addons.apt
- remove MAKEALL
- split mpc85xx boards
- remove TEST_CONFIG_CMD, just info
- fetch mips toolchain via buildman
- remove --list-error-boards param
- conditional script
- use TOOLCHAIN instead of INSTALL_TOOLCHAIN
- add aarch64
- enable notifications via email

Signed-off-by: Roger Meier <r.meier@siemens.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Tom Rini <trini@ti.com>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Andreas Färber <afaerber@suse.de>
Tested-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Acked-by: Heiko Schocher <hs@denx.de>