Fix vim-tmux-navigator version checks

When run as TPM plugin, update version check pattern to match more esoteric tmux versions (christoomey#276)

Author: strazto

vim-tmux-navigator.tmux

@@ -1,16 +1,22 @@
 #!/usr/bin/env bash
 
+version_pat='s/^tmux[^0-9]*([.0-9]+).*/\1/p'
+
 is_vim="ps -o state= -o comm= -t '#{pane_tty}' \
     | grep -iqE '^[^TXZ ]+ +(\\S+\\/)?g?(view|n?vim?x?)(diff)?$'"
-tmux bind-key -n C-h if-shell "$is_vim" "send-keys C-h"  "select-pane -L"
-tmux bind-key -n C-j if-shell "$is_vim" "send-keys C-j"  "select-pane -D"
-tmux bind-key -n C-k if-shell "$is_vim" "send-keys C-k"  "select-pane -U"
-tmux bind-key -n C-l if-shell "$is_vim" "send-keys C-l"  "select-pane -R"
-tmux_version='$(tmux -V | sed -En "s/^tmux ([0-9]+(.[0-9]+)?).*/\1/p")'
-if-shell -b '[ "$(echo "$tmux_version < 3.0" | bc)" = 1 ]' \
-    "bind-key -n 'C-\\' if-shell \"$is_vim\" 'send-keys C-\\'  'select-pane -l'"
-if-shell -b '[ "$(echo "$tmux_version >= 3.0" | bc)" = 1 ]' \
-    "bind-key -n 'C-\\' if-shell \"$is_vim\" 'send-keys C-\\\\'  'select-pane -l'"
+tmux bind-key -n C-h if-shell "$is_vim" "send-keys C-h" "select-pane -L"
+tmux bind-key -n C-j if-shell "$is_vim" "send-keys C-j" "select-pane -D"
+tmux bind-key -n C-k if-shell "$is_vim" "send-keys C-k" "select-pane -U"
+tmux bind-key -n C-l if-shell "$is_vim" "send-keys C-l" "select-pane -R"
+tmux_version="$(tmux -V | sed -En "$version_pat")"
+tmux setenv -g tmux_version "$tmux_version"
+
+#echo "{'version' : '${tmux_version}', 'sed_pat' : '${version_pat}' }" > ~/.tmux_version.json
+
+tmux if-shell -b '[ "$(echo "$tmux_version < 3.0" | bc)" = 1 ]' \
+  "bind-key -n 'C-\\' if-shell \"$is_vim\" 'send-keys C-\\'  'select-pane -l'"
+tmux if-shell -b '[ "$(echo "$tmux_version >= 3.0" | bc)" = 1 ]' \
+  "bind-key -n 'C-\\' if-shell \"$is_vim\" 'send-keys C-\\\\'  'select-pane -l'"
 
 tmux bind-key -T copy-mode-vi C-h select-pane -L
 tmux bind-key -T copy-mode-vi C-j select-pane -D