Redox OS 0.1.5 Release

This release combines a large number of changes over the past 3 weeks.
Let me know what you think!

Can’t build since running git pull:

Finished release [optimized] target(s) in 33.57 secs
x86_64-elf-ld --gc-sections -z max-page-size=0x1000 -T kernel/linkers/x86_64.ld -o build/kernel/kernel     build/kernel/libkernel.a
x86_64-elf-ld: cannot open linker script file kernel/linkers/x86_64.ld: No such file or directory 
make: *** [build/kernel/kernel] Error 1

Use make pull instead - you need to update submodules

Oh, this is a life saver. I’m still learning Rust, and trying to get my head around Redox, and having to read Git man pages at the same time is not my idea of fun. Thanks!