Fix for #925, added support for tilda in provider ipc path

[pjryan93]

What was wrong?

Tilda's are not being replaced with the users home directory on Linux and Mac.

w3 = Web3(Web3.IPCProvider("/Users/pjryan/.ethereum/testnet/geth.ipc")); 
w3.isConnected()  #returns True

w3 = Web3(Web3.IPCProvider("~/.ethereum/testnet/geth.ipc")); 
w3.isConnected() #returns False

Related to Issue #
Fix for #925.

How was it fixed?

Call expanduser() and resolve() to make sure the Tilda is replaced with the user's home directory.

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[carver]

Thanks!

Interesting: the new resolve() call is causing tests to fail when the path to the IPC file doesn't exist (or has restricted permissions). I think this is what we want, and the tests should be updated to use viable paths, like:

-('file:///root/path/to/file.ipc', IPCProvider, {'ipc_path': '/root/path/to/file.ipc'}),
+('file:///tmp/file.ipc', IPCProvider, {'ipc_path': '/tmp/file.ipc'}),

(Or presumably using a method to generate /tmp path instead, so it works across platforms.)

If this is unclear, or you get stuck please reach out and ask for help.

[carver]

Actually, since this is only breaking in python 3.5, this PR can just wait till 3.5 is dropped in web3.py v5 and merge then. I'm doing a backport to web3 v4 currently.

[carver]

You're going to rebase right @kclowes ? :)

[kclowes]

Thanks @pjryan93!