Switch to rustup

Created by: DomThePorcupine

Problem: multirust has been deprecated, we need to start using rustup!

Solution: Change the bootstrap file

Changes introduced by this pull request:

• Switch from multirust to rustup
• Add warnings that bootstrap uses curl | sh style commands to install things. I feel that I should have been warning people before, these type of commands can make people feel uncomfortable.
• Tried to start better documentation
• Added a new option, you can now run ./bootstrap -s to see the current travis build status

Fixes: #651 (closed)

State: Ready-ish

Other: I'd like some feedback on the rustInstall function and how I handle trying to install rustup/uninstall multirust. Another issue involves the $PATH environment variable and making sure it is set properly I can set it in bashrc but i worry that it might not work for people using something like zsh. @jackpot51 I'd appreciate it if a couple of you looked over things before it gets merged.