Revert "Remove dependency on wget from bootstrap."

This reverts commit d12be2748e0cd742985eb4df6bb13a50893dd224.
Default Cygwin does actually include wget, not curl.
Detect if Git or unzip is missing.
Require restart of Cygwin after installing new packages.
Remove duplicate error text.
Ignore SSL certs when using wget - causes issues behind proxy.
Attempt to fix permissions of tools in Windows with no luck yet.
Only use patch from Cygwin, not e.g. WinAVR.
Split up install commands to be able to use in a generic way.
detect if check is installed now that we use the native arch.
Merge branch 'next' into windows-bootstrap

Conflicts:
	script/bootstrap.sh
Note that compiling from source works on all platforms.
Support GCC for ARM installed in either 64- or 32-bit program files directories.
Require 'curl' package in Cygwin and subsequently use curl on every platform.
Fix logic for trying to find GCC for ARM binaries in Windows.
Require 'gcc' in Cygwin so we can use ld to test for check.
Require gcc4 in Cygwin to get modern compiler.
Check for the argparse Python module in Cygwin - doesn't com with 2.6.
Note requirement of extra Cygwin packages to use Git over HTTPS.
Merge branch 'windows-bootstrap' into next