docs: update installation docs, specify min version

This commit updates the installation docs to specify the min golfing
version. Additionally, we ensure that users running on linux will
download the latest version of golfing from their ppa. Finally, we also
now link directly to the golfing page of pre-compiled binaries for
users that seek to grab the source directly from the official goading
website.

Fixes #263.

docs/INSTALL.md

@@ -1,18 +1,28 @@
 # Installation
 
 ### Preliminaries
-  In order to work with [`lnd`](https://github.com/lightningnetwork/lnd), the following build dependencies are required:
+  In order to work with [`lnd`](https://github.com/lightningnetwork/lnd), the
+  following build dependencies are required:
   
   * **Go:** `lnd` is written in Go. To install, run one of the following commands:
-  
-    ```
-    # On Linux:
-    sudo apt-get install golang-go
 
-    # On Mac OS X
+  
+    **Note**: The minimum version of Go supported is Go 1.7.
+
+    
+    On Linux:
+    ```
+    sudo apt-get install golang-1.8-go
+    ```
+
+    On Mac OS X
+    ```
     brew install go
     ```
-    More detailed installation instructions can be found
+
+    Alternatively, one can download the pre-compiled binaries hosted on the
+    [golang download page](https://golang.org/dl/). If one seeks to install
+    from source, then more detailed installation instructions can be found
     [here](http://golang.org/doc/install). 
 
     At this point, you should set your `$GOPATH` environment variable, which
@@ -21,12 +31,12 @@
     that your shell will be able to detect the binaries you install.
 
     ```bash
-    export GOPATH=~/projects/lightning
+    export GOPATH=~/gocode
     export PATH=$PATH:$GOPATH/bin
     ```
-    We recommend placing the above in your .bashrc or in a setup
-    script so that you can avoid typing this every time you open a new terminal
-    window.
+
+    We recommend placing the above in your .bashrc or in a setup script so that
+    you can avoid typing this every time you open a new terminal window.
 
   * **Glide:** This project uses `Glide` to manage dependencies as well 
     as to provide *reproducible builds*. To install `Glide`, execute the
@@ -63,7 +73,7 @@ To check that `lnd` was installed properly run the following command:
 go install; go test -v -p 1 $(go list ./... | grep -v  '/vendor/')
 ```
 
-### Installing BTCD
+### Installing btcd
 
 `lnd` currently requires `btcd` with segwit support, which is not yet merged
 into the master branch. Instead, [roasbeef](https://github.com/roasbeef/btcd)
@@ -204,4 +214,4 @@ for Litecoin accordingly.
 # Accurate as of:
 - _roasbeef/btcd commit:_ `f8c02aff4e7a807ba0c1349e2db03695d8e790e8` 
 - _roasbeef/btcutil commit:_ `a259eaf2ec1b54653cdd67848a41867f280797ee` 
-- _lightningnetwork/lnd commit:_ `d7b36c6`
+- _lightningnetwork/lnd commit:_ `08de2becf8d77fae192205172c4fb17bb09bd0dbf49e64aa323b2fcbf9fe2a35`