Support quoted components in Windows %PATH%

• Your Windows build number: 10.0.15063
• What's going wrong: When invoking bash from a windows command prompt, the translation of the windows PATH environment variable is befuddled by quotes and/or spaces.

1. Quoted paths in the PATH are dropped from bash's PATH :

C:\Users\nonpriv>path c:\Windows\System32;"c:\Program Files\nodejs"
C:\Users\nonpriv>node -v
v6.10.3
C:\Users\nonpriv>bash -c printenv | findstr PATH
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/mnt/c/Windows/System32
C:\Users\nonpriv>bash -c node -v
-v: node: command not found

2. Non-quoted paths containing spaces do appear inside the bash environment, but don't work properly:

C:\Users\nonpriv>path c:\Windows\System32;c:\Program Files\nodejs

C:\Users\nonpriv>bash -c printenv | findstr PATH
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/mnt/c/Windows/System32:/mnt/c/Program Files/nodejs

C:\Users\nonpriv>bash -c node -v
-v: node: command not found

Reproduce both quoted and unquoted PATH cases from a Windows command prompt using the provided path, bash, printenv, findstr, and node commands. Compare the resulting PATH and node lookup behavior; done means quoted and space-containing Windows PATH components are preserved and node -v works from bash. No source file or test is named in the issue.