Long sn fix (#499)

* Improve tasks.py

- Works from any subdir now

* Update stock detail display

* FIx width of "serial" column in stock item list

tasks.py

@@ -1,5 +1,6 @@
 """Invoke tasks for building the app"""
 
+import os
 import sys
 from invoke import task
 
@@ -13,8 +14,13 @@ def clean(c):
 @task
 def translate(c):
     """Update translation files"""
+
+    here = os.path.dirname(__file__)
+    l10_dir = os.path.join(here, 'lib', 'l10n')
+    l10_dir = os.path.abspath(l10_dir)
+
     python = 'python3' if sys.platform.lower() == 'darwin' else 'python'
-    c.run(f"cd lib/l10n && {python} collect_translations.py")
+    c.run(f"cd {l10_dir} && {python} collect_translations.py")
 
 
 @task(pre=[clean, translate])