Add root .gitignore file to cleanup ignore lists

This removes need for local configuration to ignore *.o and *~
and allows the src/*/.gitignore files to be removed (subdirectories
will inherit the rules from the root .gitignore).

.gitignore

@@ -0,0 +1,3 @@
+*.o
+*.d
+*~

src/common/.gitignore

@@ -1 +0,0 @@
-*.d

src/crypto/.gitignore

@@ -1 +0,0 @@
-*.d

src/drivers/.gitignore

@@ -1 +0,0 @@
-*.d

src/eap_common/.gitignore

@@ -1 +0,0 @@
-*.d

src/eap_peer/.gitignore

@@ -1 +0,0 @@
-*.d

src/eap_server/.gitignore

@@ -1 +0,0 @@
-*.d

src/eapol_supp/.gitignore

@@ -1 +0,0 @@
-*.d

src/hlr_auc_gw/.gitignore

@@ -1 +0,0 @@
-*.d

src/l2_packet/.gitignore

@@ -1 +0,0 @@
-*.d

src/radius/.gitignore

@@ -1 +0,0 @@
-*.d

src/rsn_supp/.gitignore

@@ -1 +0,0 @@
-*.d

src/tls/.gitignore

@@ -1 +0,0 @@
-*.d

src/utils/.gitignore

@@ -1 +0,0 @@
-*.d

src/wps/.gitignore

@@ -1 +0,0 @@
-*.d