Add .issig files of the prebuilt files so synch-isfiles.bat will find them right away without first requiring a run of build.bat or build-ce.bat.

Files/isbzip.dll.issig

@@ -0,0 +1,6 @@
+format issig-v1
+file-size 39200
+file-hash 8072e83385afc4a84006271a87a11fc0a22b149cbd77322669ca56c470d28ced
+key-id c2587f3885b12463bafdadb799f23435f26c03944c1afc1716aabc6a43f2426f
+sig-r bca59deb05b13ed348a86c2f1a0a122ab7918d3ce9c1f334a0f7e847b2a7d00f
+sig-s 52b92c7186141b28966e68d27e8357bf478c9be3a4200d7622f8aff8789e1339

Files/islzma.dll.issig

@@ -0,0 +1,6 @@
+format issig-v1
+file-size 135816
+file-hash b252471e95f0853902b15ae71a90574f9b168f8d4a0c474b20537511f90220a5
+key-id c2587f3885b12463bafdadb799f23435f26c03944c1afc1716aabc6a43f2426f
+sig-r 5fce3235693dde5e7859fba559f7ff2e63e782f7223cdadef3d2a66b67521a34
+sig-s 1799f357e4c8c8938478ccdd7f39695ee4ba31fdee7e70a3d7940e98b59efc9c

Files/isscint.dll.issig

@@ -0,0 +1,6 @@
+format issig-v1
+file-size 795776
+file-hash 5ae5dcd47ae9cd0929e0d6b2591e2ecc14cb8dfe4e04fb37a6cef5f1896edd11
+key-id c2587f3885b12463bafdadb799f23435f26c03944c1afc1716aabc6a43f2426f
+sig-r 1c8ae696220689a1654b55c92ebdd7df4ba760f47ff49b8e2e034da15a128745
+sig-s 80d16b8a32537de7fc31c7b24965c27934f949a2a06c5d0de5cfad4ea89b6248

Files/iszlib.dll.issig

@@ -0,0 +1,6 @@
+format issig-v1
+file-size 34592
+file-hash 14c0d4a2a41572384f8309cdf03de5c6e7ed46bef64cce70d989b2665eff1a47
+key-id c2587f3885b12463bafdadb799f23435f26c03944c1afc1716aabc6a43f2426f
+sig-r dbf63b422c825ffcab7c75cb09d6043964fb1cd10f8943421e382eb1d14a9d8a
+sig-s 8d013d89014aab0345489f5844e29bc521d25c1209450951a134059d9fd8b8c4