Add .spl and .soc

- .soc - package changes
- .spl - documentclass elsarticle (Elsevier journals)

Source: http://tex.stackexchange.com/a/256803/9075

TeX.gitignore

@@ -56,9 +56,15 @@ acs-*.bib
 *.snm
 *.vrb
 
+# changes
+*.soc
+
 # cprotect
 *.cpt
 
+# elsarticle (documentclass of Elsevier journals)
+*.spl
+
 # endnotes
 *.ent