added -s (install from source) option.

nvm.sh

@@ -151,7 +151,7 @@ nvm()
       echo
       echo "Usage:"
       echo "    nvm help                    Show this message"
-      echo "    nvm install <version>       Download and install a <version>"
+      echo "    nvm install [-s] <version>  Download and install a <version>"
       echo "    nvm uninstall <version>     Uninstall a version"
       echo "    nvm use <version>           Modify PATH to use <version>"
       echo "    nvm run <version> [<args>]  Run <version> with <args> as arguments"
@@ -180,6 +180,7 @@ nvm()
       local sum
       local tarball
       local shasum='shasum'
+      local nobinary
 
       if [ ! `which curl` ]; then
         echo 'NVM Needs curl to proceed.' >&2;
@@ -193,10 +194,20 @@ nvm()
         nvm help
         return
       fi
-      VERSION=`nvm_remote_version $2`
-      ADDITIONAL_PARAMETERS=''
+
       shift
+
+      nobinary=0
+      if [ "$1" = "-s" ]; then
+        nobinary=1
+        shift
+      fi
+
+      VERSION=`nvm_remote_version $1`
+      ADDITIONAL_PARAMETERS=''
+
       shift
+
       while [ $# -ne 0 ]
       do
         ADDITIONAL_PARAMETERS="$ADDITIONAL_PARAMETERS $1"
@@ -205,6 +216,8 @@ nvm()
 
       [ -d "$NVM_DIR/$VERSION" ] && echo "$VERSION is already installed." && return
 
+      # skip binary install if no binary option specified.
+      if [ $nobinary -ne 1 ]; then
         # shortcut - try the binary if possible.
         if [ -n "$os" ]; then
           binavail=
@@ -236,6 +249,7 @@ nvm()
             fi
           fi
         fi
+      fi
 
       echo "Additional options while compiling: $ADDITIONAL_PARAMETERS"