Bugfix: Grammar fixes

doc/gitian-building.md

@@ -87,7 +87,7 @@ After creating the VM, we need to configure it.
 
 ![](gitian-building/network_settings.png)
 
-- Click `Advanced`, then `Port Forwarding`. We want to set up a port through where we can reach the VM to get files in and out.
+- Click `Advanced`, then `Port Forwarding`. We want to set up a port through which we can reach the VM to get files in and out.
 - Create a new rule by clicking the plus icon.
 
 ![](gitian-building/port_forwarding_rules.png)
@@ -111,7 +111,7 @@ Installing Debian
 
 This section will explain how to install Debian on the newly created VM.
 
-- Choose the non-graphical installer.  We do not need the graphical environment, it will only increase installation time and disk usage.
+- Choose the non-graphical installer.  We do not need the graphical environment; it will only increase installation time and disk usage.
 
 ![](gitian-building/debian_install_1_boot_menu.png)
 
@@ -144,7 +144,7 @@ and proceed, just press `Enter`. To select a different button, press `Tab`.
 
 ![](gitian-building/debian_install_9_user_password.png)
 
-- The installer will set up the clock using a time server, this process should be automatic
+- The installer will set up the clock using a time server; this process should be automatic
 - Set up the clock: choose a time zone (depends on the locale settings that you picked earlier; specifics don't matter)  
 
 ![](gitian-building/debian_install_10_configure_clock.png)
@@ -371,7 +371,7 @@ COMMIT=2014_03_windows_unicode_path
 Signing externally
 -------------------
 
-If you want to do the PGP signing on another device that's also possible; just define `SIGNER` as mentioned
+If you want to do the PGP signing on another device, that's also possible; just define `SIGNER` as mentioned
 and follow the steps in the build process as normal.
 
     gpg: skipped "laanwj": secret key not available