Reimplement browse according to hub
Manually parse browse url flag
Remove deprecated flag
Move PushTarget to Branch
Check null of trackedBranch
Only set head when it's empty
Fix browse help
Merge pull request #510 from github/browse_compat

gh: Browse Compatibility
Point path to ~/.config/hub
Pull in github.com/BurntSushi/toml
Refactor to use toml for config

* Rename Credentials to Credential
* Use toml for config
Rename Config.DefaultCredential()
Fix cukes setup steps to use toml
One Credential
Use array of table for config format
Change config sample in test to reflect what's expected

We'll store the host name with scheme instead of the API endpoint
Match the new array of table TOML format
Add stub block for loading from YAML
Use current user's login for config user name
Fix OAuthAppURL