get rid of categories and add more tags

Signed-off-by: Harald Hoyer <harald@hoyer.xyz>

content/2015/02/25/single-uefi-executable-for-kernelinitrdcmdline.md

@@ -1,6 +1,8 @@
 +++
 title = "Single UEFI executable for kernel+initrd+cmdline"
 date = 2015-02-25T15:55:16+00:00
+[taxonomies]
+tags = ["UEFI", "fedora", "SecureBoot"]
 +++
 
 Lately Kay Sievers and David Herrmann created a UEFI

content/2015/03/05/libtool-getting-rid-of-180000-sed-forks.md

@@ -1,6 +1,8 @@
 +++
 title = "libtool: getting rid of 180,000 sed forks"
 date = 2015-03-05T08:10:36+00:00
+[taxonomies]
+tags = ["fedora", "programming"]
 +++
 When compiling systemd on rawhide, we noticed a significant slowdown in compile time. 
 Investigating further, it turns out, that libtool forks an incredible amount of sed. 

content/2015/10/13/a-python-transaction-class.md

@@ -1,6 +1,8 @@
 +++
 title = "A Python Transaction Class"
 date = 2015-10-13T10:20:43+00:00
+[taxonomies]
+tags = ["python", "programming"]
 +++
 This is a repost of a blog post of 2008. Just for the reference :-)